To cut a long story short, I have a 1990 Tristar with Holley 4160 on Ford 351W. List 50419-1. Removed carb and dissassembled all components that did not need positional resetting except idle mixture screws.

Used carb cleaner and compressed air and blew out all channels. THere was not much dirt but I thought that this could not hurt. Reassembled and relocated carb on engine and ran engine (at home). The problem I am having now is that there is LOTS of smoke coming out of both exhausts that I did not have before. So for some reason the system is running very rich. It idles ok around 600 rpm and accelerates as before and there is no bogging or hesitation (unloaded ). The idle screws were reinstalled and set to about 1 1/8 turns out from seated - as they were before I removed them.

SOme people are telling me that the float chamber is dumping fuel down the intake and I need to set my float level. There is no sight opening or external needle seat adjusting screws.

Is this most likely the problem ? - If so how do I set the float level?
or is it something else?

These carbs don't really have too much to adjust so I don't know what I did that richened the mixture if that's what is happening.

Lolly....
If I remember correctly(it's been a few years since I adjusted float on a Holley) the big headed slot screw with locknut on top of bowls ahead of fuel line is for adjustment. The screw on the side of the bowls are for the float level. Take screws out of the side, start your engine and adjust float until gas is at the height of bottom of hole. If your worried that they may be too high now, it may be a good idea to lower them before starting engine so the gas doesn't come out all over your manifold.

It may also be just a piece of dirt under the needle. You can take needles out to check. Or it may just be adjusted a bit rich.I can't remember how far open mine are, but Holleys can be a bit fussy with air mixture. Last fall I adjusted mine and it runs fine, but a bit rich. I'll have to do it again.

If anything sounds wrong about this to anyone else, please correct me. Like I said, it's been a few years.